import React, { Component } from 'react'

export default class Demo extends Component {

  state = { count: 0 }

  add = () => {

    // 对象式的setState
    // const { count } = this.state
    // this.setState({ count: count + 1 }, () => {
    //   console.log('回调count', this.state.count);
    // })
    // console.log('非回调count', this.state.count);

    // 函数式的setState
    this.setState(state => ({ count: state.count + 1 }), () => {
      console.log(this.state.count);
    })

    // this.setState({ count: this.state.count + 1 })
  }

  render() {
    return (
      <div>
        <h1>当前求和为：{this.state.count}</h1>
        <button onClick={this.add}>点我+1</button>
      </div>
    )
  }
}
